Liquid crystal phase and waterlike anomalies in a core-softened shoulder-dumbbells system

Abstract

Using molecular dynamics we investigate the thermodynamics, dynamics and structure of 250 diatomic molecules interacting by a core-softened potential. This system exhibits thermodynamics, dynamics and structural anomalies: a maximum in density-temperature plane at constante pressure and maximum and minimum points in the diffusivity and translational order parameter against density at constant temperature. Starting with very dense systems and decreasing density the mobility at low temperatures first increases, reach a maximum, then decreases, reach a minimum and finally increases. In the pressure-temperature phase diagram the line of maximum translational order parameter is located outside the line of diffusivity extrema that is enclosing the temperature of maximum density line. We compare our results with the monomeric system showing that the anisotropy due to the dumbbell leads to a much larger solid phase and to the appearance of a liquid crystal phase. the double ranged thermodynamic and dynamic anomalies.

14 pages, 5 figures

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• Waterlike Features, Liquid-Crystal Phase and Self-Assembly in Janus Dumbbells
• Anomalous diffusion and diffusion anomaly in confined Janus dumbbells
• Confinement effects on the properties of Janus dimers
• Critical points, phase transitions and water-like anomalies for an isotropic two length scale potential with increasing attractive well
• Density and structural anomalies in soft-repulsive dimeric fluids
• Ion-Wake induced anomaly of Dust Lattice Mode in presence of external Magnetic field
• Hydration and anomalous solubility of the Bell-Lavis model as solvent
• Integral equation study of soft-repulsive dimeric fluids